I have a Concord grapevine that was planted 8 years ago. Each year, it usually bears a ton of grapes. This year, however, it's very slim pickings. I don't think the weather is the culprit, because I have 2 other grapevines (Niagara and Delaware), and both have a ton of grapes on them this year.

Is this anything to be concerned about? Could the grapevine possibly have Pierce's disease or something? Incidentally, I live in Northeast Georgia, zone 8A. Thanks for any info.